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» GHSA-645j-cm4x-3xvw
Description
Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader's extension-only validation (which permits PHP code in files saved with image extensions like .png), this can result in authenticated remote code execution. Concrete CMS thanks Yonatan Drori (Tenzai) for reporting this issue.
Basic information
Type
reviewed
Severity
critical Advisory on GitHub
Open advisory ↗ Repository advisory
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Source code
Browse source ↗ Published (advisory)
2026-05-21 21:30:37 UTC
Updated
2026-06-23 22:56:36 UTC
GitHub reviewed
2026-06-23 22:56:36 UTC
NVD published
2026-05-21
EPSS Score
Score
Percentile
0.74%
49.69%
CVSS Scores
Base score
Version
Severity
Vector
7.2
3.1
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CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
9.4
4.0
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CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:H)
High privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:H)
High confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:H)
High integrity impact on subsequent systems.
Subsequent system availability impact (SA:H)
High availability impact on subsequent systems.
CWEs
CWE id
Name
CWE-23
Relative Path Traversal
Affected packages (1)
Vulnerable version ranges and first patched releases as published by GitHub.
Ecosystem
Package
Vulnerable range
First patched
Vulnerable functions
composer
concrete5/concrete5 < 9.5.1
9.5.1
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cvelogic
Threat Intelligence